Method of recovering diisocyanates from liquid residue of their distrillation

专利摘要:

公开号:SU983124A1
申请号:SU762389494
申请日:1976-08-13
公开日:1982-12-23
发明作者:Мюке Гюнтер；Штароста Дитер
申请人:Феб Зюнтезеверк Шварцхайде (Инопредприятие)；
IPC主号:

专利说明:

 (54) METHOD FOR THE IMPLEMENTATION OF ORGANIC DIISOCYANATES FROM A LIQUID RESIDUE OF THEIR DISTILLATION
I
The invention relates to the field of continuous. thermal separation of organic isocyanates from a liquid distillation residue, which are formed during the preparation of organic isocyanates as a result of the phosgenation of amines.5
These distillation residues contain organic isocyanates with an NCO-group content of approximately 30%. Since organically isrcyanates are very expensive and highly finished products, their regeneration is necessary for both environmental considerations and economic considerations. The treatment of the distillation residue is very difficult, since when the content of NCO-groups is about 25% by weight, a very high viscosity increase is observed, and the residue of distillation is prone to polymerization.
A known method for separating organic isocyanates from a liquid residue is distilled, during which the distillation residues under pressure 20 are heated to 200-300 ° C, after which the overheated distillation residues are sent in the form of droplets to a reduced pressure zone (1-50 mm Hg Art.), where the isocyanates evaporate without additional sub-125
water is warm. After that, the pure isocyanates condense, and the distillation residues with a small amount of isocyanates remain as a viscous liquid or in solid form in an evaporator. In this method, all the heat required for evaporation is supplied by overheating the original product, and the superheat temperature is limited above the maximum heating temperature of 300 ° C. 11 However, isocyanate losses increase due to polymerization as the temperature of the polymers is not sufficiently reverse. When bopy. The concentration of nococyanates of the mixture supplied to overheat the heat is not enough to completely evaporate the isodate. The resulting residue also contains isocyanates, as a result of which it is tacky, and it is difficult to get it from the evaporator. During evaporation, as the content of the isocyanates decreases, the evaporation temperature decreases and the aging deteriorates. The aim of the invention is to increase the yield of target products and simplify the process. The goal is achieved by the fact that, according to the method of isolation, organic diisocyanates, which consists in the fact that the bottoms residue is subjected to distillation under vacuum in two stages, in the first stage in a thin film is heated in 5-20 seconds to 250-350 ° C and in the second stage, in 5–10 minutes to 300–430 ° C and in a vacuum, 1–50 Torr, and the resulting solid film of residue is ground and removed from the evaporator in the form of a granular powder. A distinctive feature of the method is distillation in two stages in a vacuum of 150 Torr, the first stage is carried out at a temperature of 250-350 ° C in 5-20 seconds, and the second at a temperature of 5-10 minutes, followed by removal of the solid film of the residue in powder form. The method is carried out as follows. The distillation residue, which is obtained by the phosgenation of amines, is treated to a thin liquid as a result of spraying or layering. This liquid layer is quickly heated to a temperature exceeding the boiling point of the organic isocyanate by 100–200 ° C in a short time. This takes 5–20 s. After that, the temperature is slow, i.e., it is increased in 5-10 minutes so that it is at least 260 ° C higher than the boiling point of the dioisot. Such an order of temperature is maintained until complete evaporation of the isocyanate. As a result of this measure, a thin and free Of isocyanate layer is obtained after evaporation, which can be easily broken. The resulting solid can be easily transported. Example 1. Distillation residue after preparation of toluene diisocyanate (TDI) with an NCO-Vpynn content of 29.5 wt.% After heating to the boiling point at 5 mm pt. Art. as; approximately 1 mm of thickness, the layer of liquid is heated at a pressure of 5 mm of mercury. Art. for 10 s to 200 ° C and as a result of the subsequent supply of heat for 5.5 min, heated to 300 ° C. Heating of the liquid layer occurs as a result of heat exchange with an electrically heated Cr.Ni steel plate, which is so measured and heated, its heat capacity, fills the need to quickly heat the liquid layer to 200 ° C and evaporate a significant part of toluene diisocyanate. The strongly porous dry residue obtained in this way with an N – CO-group content below the defined limit of 0.1 wt.%. The residue is milled cooled to 250 ° C and then placed in irrigated form. The evaporated condensate product at a temperature of approximately 40t :. Its NCO-rpynn content is 47.0 wt.%. When pre-positioned, the distillation residue consists of toluene diisocyanate and a high molecular weight compound, free from NCO-rpynn, the yield of toluene diisocyanate is 89%. Example 2. 4.4 kg / h of the distillation residue in the production of tolandstock diisocyanate formed during the phosgenation of amines is directed to the evaporation stage. The pre-heated to 130 ° C distillation residue containing 29.2% by weight of NCO-rpynn and 31% by weight of toluylene diisocyanate (TDI) has a viscosity of 1600 cP. In the first stage, the distillate residue, which is in the form of a liquid film, 2 mm thick, is heated at a pressure of 5 mm Hg. Art. within 8 minutes to a temperature of 350 ° C. The heating of the film is carried out by heat exchange with an electrically heated nickel-chrome steel plate. At this time, the plate is heated in such a way that the heat transferred from it to the film is sufficient to quickly heat the latter. When the distillation residue is heated to 250, and then 350 ° C, respectively, the TDI evaporates. At the same time, at such high temperatures, the resulting polymers break down, and at the same time TDI is formed, which immediately evaporates. Evaporated TDI covdensate at 30 ° C. 2.22 kg of condensate containing 48.1% by weight of NCO-rpynn and 98.3% by weight of TDI are obtained per hour. Thus, the NCO-rpynn yield is 83.3%, and the TDI is 160.4%. When TDI is evaporated, a dry porous residue (1.97 kg / h) is obtained, containing 0.2% by weight of NCO-group and exactly 0.1. wt.% TDI. The residue is crushed and cooled. Other residues are processed in the same way. In tab. 1 and 2, the process parameters for processing the TDI residue (example; 3) and 4,4-diphenylmethane diisocyanate residue (MDI residue) (example 4) are given.
Table 1
distillation rate Viscosity, cps
Preheating temperature, ° С
Mass flow rate, kg / h Content of YSO-groups, - weight.% Content of TDI, wt.%
The content of MDI, wt.% Ondensat
Mass flow rate, kg / h Content NCO-rpyrm, wt.% Content TDI, wt.%
MDI content, wt.% Stock after evaporation (solid)
Mass flow rate, kg / h NCO-rpynn content, wt.% TDI content, Bed.% MDI content, wt.% Of the word
Preheating temperature, C
Pressure, mm Hg. Art.
Film thickness, mm
I
First heating stage: heating time, s
temperature, ° С
The second stage of heating: heating time, min temperature, ° C
1600
100
400
Indicators
Temperature of condensation, С Output NCO-rpynn,% Output TDI,% Output MDI,%
Indicators
tkrratOK Distillation Viscosity, cps
Preheating temperature, C Weight flow, kg / h NCO content., Wt.% TDI content, wt.%
Condeisat
Weight flow, kg / h
NCO content, wt.% TDI content, wt.% Evaporation (solid)
Weight flow, kg / h

NC6-content, wt.% TDI-content, wt.% Process conditions Heating temperature, ° С Pressure, Torr
Remainder
Remainder
DISTT 1LLYDISTILLATION
TSIOSH1YY
TDI TDI)
(example 4) (example 3)
thirty
50
82.7 82.1 120.7
152 Table 2
TDI-residue peregrnki (example 5)
About 1800 130 3.11
27.1 29.9
1.26
46.4 97.8
1.74 0.4 0.2
130 50
Layer thickness, mm First st, adi heating;
heating time, s
temperature, ° C. Second heating stage:

权利要求:
Claims (1)
[1]
Invention Formula
Method for the incorporation of organic diisocyanates of the general formula
R) 2
where R is 2.4 and 2,6-toluene, 4,4-diphenylmethane or 2,6-hexamethylene from the bottom distillation residue by thermal distillation in a vacuum of G-50 mm Hg. Art., characterized in that, in order to increase the yield of the target products and to improve it,
10 Extended long table. 2
2
About 2
20 3 (S
In the first stage, the distillation residue in a thin film is heated in 5–20 s to 250–350 ° C and in the second stage in 5–10 Mia to 300–430 ° C, and the resulting solid film is crushed removed from the evaporator as a free-flowing powder.
Sources of information taken into account in the examination 1. US Patent No. 2706169, cl. 203-88, 1955 (prototype)

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同族专利:

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公开号 | 公开日

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DD130143B1|1979-12-27|

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FR2320938A1|1977-03-11|

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DD130143A1|1978-03-08|

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FR2320938B1|1980-05-30|

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GB1520055A|1978-08-02|

引用文献:

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公开号 | 申请日 | 公开日 | 申请人 | 专利标题

---

---

US3457291A|1965-04-01|1969-07-22|Union Carbide Corp|Production of isocyanates|

---

US3405040A|1965-08-31|1968-10-08|Mobay Chemical Corp|Method for recovering tolylene diisocyanate|

---

US3694323A|1968-08-05|1972-09-26|Du Pont|Separation of distillable isocyanates from their phosgenation masses|

---

CH506322A|1969-03-17|1971-04-30|List Heinz|Multi-spindle mixing and kneading machine|

---

DE2035731C3|1970-07-18|1985-08-29|Bayer Ag, 5090 Leverkusen|Process for the one-step continuous separation of distillation residues from crude isocyanates|FR2397396B1|1977-07-12|1980-01-18|Ugine Kuhlmann|

---

DE2915830A1|1979-04-19|1980-10-23|Basf Ag|PRODUCTION OF TOLUYLENE DIISOCYANATE AND / OR HIGH-BOILING SOLVENTS IN THE FLUID BED FROM DISTILLATION RESIDUES OF THE TOLUYLENE DIISOCANATE PRODUCTION|

---

SE450641B|1983-02-01|1987-07-13|Johnson Axel Eng Ab|SET FOR SEPARATION OF WATER-SOLUBLE COMPOUNDS AFTER EVAPORATION OF WATER SUSPENDED IN OIL AND USE OF THE PROCEDURE|

---

SE8604441L|1986-10-20|1988-04-21|Nobel Chematur Ab|PUT TO EXPLORE ISOCYANATES|

---

EP0520377B1|1991-06-26|1998-02-25|Lucky Ltd.|A process for the selective preparation of 4,4-methylene-bis-|

---

DE4127514A1|1991-08-20|1993-02-25|Bayer Ag|METHOD FOR PRODUCING POLYISOCYANATES FROM DISTILLATION RESIDUES OF THE TOLUYLENE DIISOCYANATE PRODUCTION|

法律状态:

优先权:

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申请号 | 申请日 | 专利标题

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DD18786675A|DD130143B1|1975-08-15|1975-08-15|METHOD FOR CONTINUOUS THERMAL SEPARATION OF ORGANIC ISOCYANATES FROM LIQUID DISTILLATION RESIDUE|

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